This invention refers to an overload control device between two joined together rotating machine parts. There are at least two essentially semi-cylindrical projections radially extending from the machine parts, and uniformly distributed over the circumference. Two projections, with one each from a different machine part form cylinders, with a divider line or partition line parallel with the path of rotation of the machine parts. Each two projections are embraced by hollow cylindrical carrier links made of high-duty stiff material under initial stress, while stripper cams are arranged between the projections.
This invention is related to the invention disclosed in U.S. Pat. No. 3,975,923, issued Aug. 24, 1976, which is hereby incorporated by reference in its entirety. U.S. Pat. No. 3,975,923 suggests an overload control, particularly between the driving and the driven part of a shaft, with the overload point is safely predetermined with the least possible tolerance, and where damages to the clutch parts by broken carrier links are safely eliminated. The carrier links according to the invention may be exchanged within a very brief period of time, in case of breakage, and furthermore the condition of the carrier links may be easily checked during maintenance work.
As is the case with any machine part, this clutch, too, may show wear in certain cases after prolonged operation. Standard clutches of smaller sizes can then be disassembled during regular maintenance work in order to re-finish the semi-cylindrical projections. After assembly, the projections are connected by new carrier links. Quite often, however, there is not sufficient room to dismantle the machine parts without extensive disassembly, particularly when the overload control was subsequently added to existing installations by retrofitting. Furthermore, the finishing of semi-cylindrical projections evolved from large structural parts can be rather involved and expensive in overload controls of large dimensions.
Based on the foregoing, the present invention aims to extend the advantages of the overload control proposed by U.S. Pat. No. 3,975,923 to assembly and finishing of the machine parts, in order to obtain a more economical application of the overload control. This is achieved by arranging the projections and, if possible, at least part of the stripper cams on the machine parts in a detachable fashion. After wear, which occurs, for example, after long operating periods or because of faulty maintenance, in the semi-cylindrical projections, only the projections or at least only a small part of the entire structural part of the clutch need be removed and re-finished or exchanged.
It is a feature of the invention that the semi-cylindrical projections are components of a plate with a larger base surface and smaller lateral surfaces, and the level partition mating surfaces of each projection, parallel with the sense of rotation of the machine parts, are roughly on a level with one lateral surface of the plate. The plate with semi-cylindrical projection attached to the machine part is easily finished, once detached from the machine part. For built-in clutches it is not necessary to disassemble the main structural parts. Exchange of the projections is done easily and quickly. Preferably, the plates with their projections are connected to their respective machine part in a form-fitting manner to transmit the active forces to the machine part. This can, for example, be accomplished by flanging or grooving, whereby it is also possible to provide adjustable intermediate links as adapters. Also, the plates with their projections are fitted into recesses in the machine parts and fixed by detachable machine elements. In this way, the projections are very securely attached to the machine parts, and the active forces are absolutely safely transmitted from one shaft part to another via the semi-cylindrical projections with their carrier links.
Another detail of the invention is to attach the plates with their projections to the machine parts by gluing. Gluing can be used as an added safety measure to the detachable machine elements. It is, however, also feasible to use only glue to hold the plates in the recesses of the machine parts. The type of glue must be selected so that the connection can be easily removed if desired. The plates, according to the invention, must be designed so that each plate accommodates arresting elements to secure the carrier link. This is to ensure that in case of deformation of the rings due to overload, the functioning of the clutch just before the shut-off point is maintained until the precaution of exchanging the rings may be taken.